Robert Montagu, 3rd Duke of Manchester was a British politician who sat in the House of Commons from 1734 until 1739 when he succeeded to the peerage as Duke of Manchester.

Duke of Manchester is a title in the Peerage of Great Britain, and the current senior title of the House of Montagu. It was created in 1719 for the politician Charles Montagu, 4th Earl of Manchester. Manchester Parish in Jamaica was named after the 5th Duke, while its capital Mandeville was named after his son and heir. The current Duke is Alexander Montagu, 13th Duke of Manchester, a controversial British and Australian citizen who lives in the United States and has served several prison sentences. He succeeded to the peerage in 2002 following the death of his father Angus Montagu, 12th Duke of Manchester, the last of the dukes to hold a seat in the House of Lords.